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Cullen R. Buie. Wang, Qianru, Ph. D. Massachusetts Institute of Technology Massachusetts Institute of Technology. Department of Mechanical Engineering. Massachusetts Institute of Technology. Department of Mechanical Engineering 2015-02-05T18:24:51Z 2015-02-05T18:24:51Z 2014 2014 http://hdl.handle.net/1721.1/93818 900636680 Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014. Cataloged from PDF version of thesis. Includes bibliographical references (pages 75-80). Low frequency insulator based dielectrophoresis (iDEP) is a promising technique to study cell surface dielectric properties. To date, iDEP has been exploited to distinguish, characterize, and manipulate particles and bacteria based on their size and general cell phenotype (e.g. gram positive vs. gram negative). However, separation of bacteria with diverse surface phenotypes but similar sizes sets a much higher demand on separation sensitivity, necessitating improvement in channel structure design in order to increase the electrical field gradient. In this work, a three dimensional insulator based dielectrophoresis (3DiDEP) microdevice is designed to achieve continuous particle sorting based on their size and, more importantly, on their surface dielectric properties. A 3D constriction is fabricated inside Poly (methyl methacrylate) (PMMA) channels using a micromilling technique. By controlling the channel geometry at the 3D constriction area, a nonuniform electric field with a large intensity gradient perpendicular to the local particle flow direction results in transverse particle deflection, driving particles into different outlet streams. With both simulation and experiments, we show that a diverse array of particles can be distinguished by 3DiDEP. This 3DiDEP sorter can be used in multiple applications in which the surface properties of cells or particles are of special interest. by Qianru Wang. S.M. 80 pages eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Mechanical Engineering. High constriction ratio continuous insulator based dielectrophoretic particle sorting Thesis application/pdf Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="4f600026-ec32-4664-a475-d364b5311601"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>High constriction ratio continuous insulator based dielectrophoretic particle sorting</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2014</PublicationDate> <Authors> <Author> <DisplayName>Wang, Qianru, Ph. D. Massachusetts Institute of Technology</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Mechanical Engineering.</Keyword> <Abstract>Low frequency insulator based dielectrophoresis (iDEP) is a promising technique to study cell surface dielectric properties. To date, iDEP has been exploited to distinguish, characterize, and manipulate particles and bacteria based on their size and general cell phenotype (e.g. gram positive vs. gram negative). However, separation of bacteria with diverse surface phenotypes but similar sizes sets a much higher demand on separation sensitivity, necessitating improvement in channel structure design in order to increase the electrical field gradient. In this work, a three dimensional insulator based dielectrophoresis (3DiDEP) microdevice is designed to achieve continuous particle sorting based on their size and, more importantly, on their surface dielectric properties. A 3D constriction is fabricated inside Poly (methyl methacrylate) (PMMA) channels using a micromilling technique. By controlling the channel geometry at the 3D constriction area, a nonuniform electric field with a large intensity gradient perpendicular to the local particle flow direction results in transverse particle deflection, driving particles into different outlet streams. With both simulation and experiments, we show that a diverse array of particles can be distinguished by 3DiDEP. This 3DiDEP sorter can be used in multiple applications in which the surface properties of cells or particles are of special interest.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>